1. Technical Field
This invention generally relates to a door assembly. More particularly, the invention relates to a fire-rated door assembly for a chute system. Specifically, the invention relates to a door assembly which includes a weld-free door having an automatic door closer mounted on the interior surface thereof and which includes a deflector plate for covering the door hinge during operation.
2. Background Information
In tall building structures like apartments or office buildings, it is common to provide chute systems which are used by the occupants of the building to dispose of trash or to send laundry to lower floors in the building.
The chute systems generally consist of a large, vertically-oriented main chute that has a plurality of branches, each of which originates in an opening on one of the individual levels of the building structure. Each opening to the chute system is provided with a door to cover that opening when the chute is not in use. The occupant can open the door and place a bag of garbage or laundry, for example, through the opening and then release the bag. The bag slides down the chute branch to the main chute and then drops or slides downwardly to a collection bin disposed a spaced number of floors away from the opening in question.
The door that covers the opening to the chute branch has to meet certain safety requirements and standards. One of those requirements is that the chute door must close automatically when released. Furthermore, the door must meet UL (Underwriters Laboratory Inc.) fire codes to attempt to prevent any fires from spreading from one floor of a building to another through the chute system.
Currently known chute door designs typically include a recessed frame that fits inside the chute opening and serves as mounting structure for the chute door. Furthermore, chute doors that are presently known in the art generally use fairly complex systems of linkages to shut the door once it is released. The inclusion of the linkage is usually a result of trying to maximize the angle of door opening while preserving the self-closing feature of the door. Other designs, such as those of U.S. Pat. Nos. 6,062,368; 6,186,306 and 6,269,928 utilize the linkages to both close the door and provide auxiliary functions such as automatic locking. The linkage and closer assemblies used in the prior art are typically mounted inside the chute or on the frame on one side of the door in order to meet the code requirements and reduce the possibility of contamination of the linkages and closer assemblies.
The aforementioned usage of linkage and closer assemblies results in deficiencies in currently known chute doors. The mounting of the linkage and closer assembly in the chute or on the side of the door takes up significant space in the chute opening and reduces the usable area of the opening for disposable of articles therethrough. When the linkage and closer assemblies are placed to the side of the door, the width of the door is necessarily decreased to allow for installation into a fixed width chute opening. Thus, the door size and the usable chute opening are both reduced. Currently known designs also have the linkages and closer attached to the frame inside the chute. As the door is opened, the mechanism remains essentially in the same position, namely inside the chute and obstructing a portion of the opening. Furthermore, the closer assembly is typically the highest maintenance and replacement item for chute doors. When the closer is fixedly mounted to a structure inside the chute, it can be difficult to access, remove and reinstall. Some known designs therefore require that the entire door assembly be pulled out of the chute for maintenance of the closer assembly.
A second deficiency in the currently known art relates to the actual installation of the door. The chute system is typically installed in the building before the finishing of the interior surfaces and installation of the chute doors. Variations in wall thickness, chute opening size, squareness of the opening etc., can require modifications to the door assembly to achieve a proper fit and function of the door. The safety standards and ratings of these types of doors require fairly precise fits and connections which may be compromised by the typical variations found in rough construction. The result is often a need to custom fit each door installation with field-cuts or modifications in order to get the door assembly to fit into rough construction. This obviously leads to an increase in the number of man hours such an installation procedure costs and therefore leads to an increase in the total cost of installation of a chute system into a building structure. Furthermore, if the installation requires field modifications, the fit and alignment of the finish frame can be adversely affected and result in an aesthetically displeasing door assembly.
Previously known doors are manufactured with the interior surfaces of the door being made of cheaper materials such as aluminized or galvanized steel and having typically been welded together. The applicant has recognized that both the type of steel used and the presence of welds tends to increase the risk of contamination of the door surfaces. This risk of contamination increases because aluminized or galvanized steel may react with accidentally spilled materials and liquids resulting in early deterioration of the interior door surface. Furthermore, welds tend to have small pitted areas therein and consequently debris from the garbage can accumulate in both the welded areas and on the deteriorating surfaces, thus allowing bacterial colonies to flourish on the door.
There is therefore a need in the art for a door assembly for a chute system that is capable of meeting regulations and codes governing this type of installation; that is easy to install and maintain, that tends to reduce the potential for contamination of the door and yet leaves the maximum amount of space available in the opening in order to allow articles to be inserted therethrough and be deposited into the chute.